This invention relates to dispensing apparatus. Particularly, but not exclusively it relates to dispensing apparatus for dispensing viscous materials from a container under pressure of a propellant.
Known dispensing apparatus commonly includes a valve mechanism fitted to a container which is refilled with a product, for example mastic or sealant, which is to be dispensed. Examples are disclosed in Patent document EP-B-0243393 (Rocep Lusol Holdings Limited). However, known arrangements have several disadvantages. For example, the cost of components used in the manufacture of such known apparatus is high. The valve mechanism comprises a large number of separate parts which must be assembled together. Automatic assembly of such apparatus is complicated and costly.
It is an object of the present invention to provide a dispensing apparatus which overcomes one or more of the above disadvantages.
According to the present invention there is provided a dispensing apparatus for dispensing a product from a container, said apparatus comprising:
a product chamber within the container;
a valve adjacent to the product chamber;
a hinge assembly;
a lever hingedly attached to the hinge assembly and having a bearing portion; and
a nozzle assembly sealingly engageable with the hinge assembly, the nozzle assembly being rotatable between open and closed positions and including an actuator portion provided with a cam surface which cooperates with the lever bearing portion such that in the open position operation of the lever causes movement of the actuator portion to open the valve and permit flow of the product out of the apparatus.
Preferably the apparatus comprises means for urging the product from the product chamber. Preferably the product chamber is pressurised. The product chamber may contain a propellant. The product chamber may contain a piston, situated between the propellant and the valve.
Preferably the valve is a tilt valve. Tilt valves are generally known in dispensing apparatus and operate by tilting of a hollow central stem which is resiliently held on a mounting cup by a rubber grommet. The stem is closed at its lower end by a sealing plate. When the stem is tilted, the seal between the grommet and the sealing plate is broken and the product can reach apertures in the central stem and thence flow along the hollow stem.
Preferably the valve comprises a mounting cup adapted to secure the valve to the container. Preferably the container is provided with a rolled flange portion and the mounting cup is provided with a corresponding flange portion adapted to engage with the rolled flange portion of the container.
Preferably the actuator portion comprises a ring member arranged at a lower end of the nozzle assembly. Preferably the cam surface comprises one or more depressions and one or more raised surfaces. Preferably when the nozzle assembly is in the closed position the lever bearing portion is adapted to bear upon one of said depressions, and when the nozzle assembly is in the open position the lever bearing portion is adapted to bear upon one of said raised surfaces.
Preferably the lever comprises two lever bearing portions arranged at opposite sides of the valve. Preferably the cam surface comprises two depressions arranged at opposite sides of the ring and two raised surfaces arranged between the depressions at opposite sides of the ring.
Preferably the nozzle assembly is provided with means to limit the rotational travel of the nozzle assembly between the closed position and the open position. These means may comprise two end stops provided on the nozzle assembly adapted to locate against an upstand on the hinge assembly.
The nozzle assembly may be provided with fin members adapted to hold the lever bearing portion against the cam surface. The fin members may be of different lengths. Preferably a fin member is provided at each depression and each raised surface of the cam surface, spaced from the cam surface to allow the insertion of the lever bearing portion between the fin member and the cam surface.
Preferably the nozzle assembly comprises one or more dog teeth and the hinge assembly comprises one or more slots, adapted such that a dog tooth can enter a slot only when the nozzle assembly is in the open position. The nozzle assembly is preferably coupled to the valve stem for longitudinal movement, such that movement of the nozzle assembly towards the container causes the dog tooth to enter the slot and the valve stem to move, thereby opening the valve to release the product.
Preferably, the container is made substantially from aluminium and is most preferably an aluminium monoblock container. Alternatively the container may be a wall ironed tin plate can, or an extruded tin plate can as used in the beverage industry, without a side seam.